CORRELATION BETWEEN THROMBOCYTOPENIA DEGREE AND PARASITE DENSITY IN CONFIRMED CASES OF Plasmodium falciparum AND Plasmodium vivax MALARIA

Background: Thrombocytopenia, a condition characterized by a low platelet count, is the most prevalent hematological abnormality observed in acute malaria patients. Malaria remains a major global public health problem, with more than 200 million clinical cases reported annually. Purpose: This study aimed to investigate the correlation between the degree of thrombocytopenia and the parasite density in confirmed cases of Plasmodium falciparum and Plasmodium vivax. Method: This research was a descriptive observational study using a cross-sectional design. Clinical hematological examinations and peripheral blood smear preparations were performed on malaria patients, followed by analysis of platelet count, hemoglobin levels, and leukocyte count. Result: Thrombocytopenia, commonly found in acute malaria, was observed in 63.4% of cases, underscoring its key role as a diagnostic biomarker. This study showed significant association between hemoglobin levels and thrombocytopenia severity (p-value < 0.05), whereas leukocyte counts did not show a significant association with thrombocytopenia severity (p-value > 0.05). The degree of thrombocytopenia differed between the two types of malaria, assisting the differentiation of infections. Anemia, another detailed hematological indicator, frequently found in P. falciparum cases. Conclusion: Understanding hematological indicator as key-role of malaria diagnosis is vital for accurate diagnosis and effective management of malaria, especially in endemic regions. Continued research and routine hematological surveillance are crucial to improving malaria control and treatment outcomes.

Introduction

Malaria is an infectious disease associated with varying degrees of hematological complications with anemia and thrombocytopenia being the most common manifestations(Sharma et al., 2017). According to the World Health Organization (WHO), approximately 40% of the global population is at risk of malaria infection. The annual incidence of malaria reported among 300 to 500 million cases, reached two million deaths each year(Arif et al., 2016). In Indonesia, there are five species of malaria exist,Plasmodium falciparum(P. falciparum),Plasmodium vivax(P. vivax),P. malariae,P. ovale, andP. knowlesi(Zein et al., 2017).

Early clinical detection of malaria is critical for its successful treatment. Diagnosis is typically performed using light microscopy to examine thick and thin blood smears, which remains the most reliable and widely applicable method for detecting malaria. The severity of malaria is associated to the parasitemia degree, with high levels of parasitemia resulting in severe malaria(Antwi-Baffour et al., 2023). Severe malaria is defined by the presence of asexual stage of malaria parasites, accompanied by serious symptoms or complications of malaria(Naing & Whittaker, 2018). SevereP. falciparummalaria is obvious shown on clinical manifestations, including decreased consciousness, multiple convulsions, acute respiratory distress, circulatory collapse or shock, acute kidney injury, prostration, clinical jaundice, and abnormal bleeding. A study conducted in Bangkok showed lower platelet count in cases of severe malaria compared to malaria without serious complications(Mon et al., 2022).

According to the latest WHO guidelines, hematological indices, including thrombocytopenia, are not considered criteria for defining severe malaria, however their clinical significance is widely recognized(Teparrukkul et al., 2019). A retrospective study involving 614 patients revealed that individuals with thrombocytopenia were more likely to develop Multi-Organ Dysfunction (MOD) and had an increased risk of mortality compared to malaria patients with normal platelet counts(Gill et al., 2013).

Thrombocytopenia is a known complication of malaria caused byP. falciparuminfection. However, recent studies have shown thatP. vivaxshow similar levels of severity(Bayleyegn et al., 2021). Hematological indices of malaria patients have reveal thrombocytopenia, which has been linked to excessive platelet sequestration and a shortened platelet lifespan(Lestari, 2019);(Muley et al., 2014). The proposed mechanisms leading to thrombocytopenia include coagulation disturbances, splenomegaly, bone marrow alterations, antibody-mediated platelet destruction, oxidative stress, and the role of platelets as cofactors in triggering severe malaria(Kumar et al., 2022);(Muley et al., 2014);(Natalia, 2014).

This study aimed to assess the importance of thrombocytopenia and its potential role as an early diagnostic marker for malaria. The presence of thrombocytopenia can serve as a noticeable clinical indicator of malaria symptoms. In addition to, this study sought to establish a correlation between the presence of thrombocytopenia and the type of malaria in regions where malaria is endemic in Indonesia.

Material and Method

This descriptive observational study employed a cross-sectional design. The research involved clinical hematological examinations and peripheral blood smears analyses of malaria patients visited a laboratory in Jayapura, which were then analyzed for platelet count, hemoglobin levels, and leukocyte count. Blood samples were collected from people with malaria who visited healthcare service units. The blood samples were stored in ethylenediaminetetraacetic acid (EDTA) tubes and used to prepare thin and thick blood films for giemsa staining and microscopic identification of malaria parasites and species. In this study, individuals with malaria were diagnosed through blood smear examination, and automated hematology analyzer used to assess hematological indicators. Trained medical laboratory scientists collected the blood samples, and blood counts were conducted using the Sysmex XP-100 hematology analyzer.

To discover the density of malaria parasites, a blood technician independently counted the asexual stagePlasmodiumparasites on slides, specifically counting 200 White Blood Cells (WBCs) in thick blood films from each malaria case. The counts from two independent technician were then averaged, and this mean value was used to calculate the parasite density. The number of parasites per microliter (μL) of blood was then determined using the following Formula (1).

\( \documentclass{article} \usepackage{amsmath} \begin{document} \displaystyle \text{Parasite}/\mu\text{L} = \frac{\text{parasite counted}}{200} \times \text{total WBC count} \quad \text{.... (1)} \end{document} \)

Platelet counts were determined by directly measuring platelet pulses and was expressed as thousands of platelets per microliter of whole blood. Thrombocytopenia was defined as a platelet count of less than 150.000/μL. Patients were categorized into three subgroups based on their platelet counts. Thrombocytopenia was considered severe if the platelet count was less than 50.000/μL, moderate if it ranged from 50.000 to 100.000/μL, and mild if it fell between 100.000 and 150.000/μL(Kumar et al., 2022).

Malaria parasite density was determined using the aforementioned formula and was categorized as mild, moderate, or severe parasitemia. Blood samples with 5 – 10.000 parasites/μL could be considered as low parasitemia corresponding to mild malaria, and those with 10.000 –100.000 parasites/μL were categorized as intermediate parasitemia indicating moderate malaria, whilst parasitemia above 100.000 parasites/μL was classified as hyper parasitemia and described as severe malaria which may lead to death(Wilairatana et al., 2013).

Thrombocytopenia and parasite density were treated as ordinal variables. To evaluate the correlation between them, the Spearman’s rank correlation test was used. A p-value of less than 0.05 was considered statistically significant.

Result

A total of 41 eligible patients were enrolled and randomly assigned in the study, with their characteristics summarized inTable 1. Among